package main

import "fmt"

func main() {
	var n int
	var s string
	var arr []int

	_, _ = fmt.Scan(&n)
	_, _ = fmt.Scan(&s)
	arr = make([]int, 2*n)
	for i := 0; i < 2*n; i++ {
		_, _ = fmt.Scan(&arr[i])
	}

	fmt.Println(2 * n)
}
